The present invention relates to a readjustment preventing structure for an adjustment member and, more particularly, to a readjustment preventing structure for an adjustment member in a carburetor.
In an apparatus including an adjustment member or a carburetor in particular, there are conventionally provided various adjustment screws such as an opening regulation screw for a throttle valve or an auto-choke valve so that a ratio, e.g. an air fuel ratio, a suction air amount and the like, can be adjusted to optimum values by these adjustment screws before the apparatus is supplied to the market.
If the adjustment screws are tampered with by the user, the air fuel ratio, the suction air amount and the like which have been preset will be changed to induce incomplete combustion of the fuel, thereby resulting in such a problem as atmosphere pollution.
As conventional means for preventing the user's readjustment, an engagement slot has been formed on the outer periphery of a head for rotating operation of an adjustment screw, and a projection to be engaged in this engagement slot has been also formed on an inner peripheral portion of an elastic cap. Thus, after adjusting the adjustment screw, the cap is press-fitted onto the head of the adjustment screw while causing the projection to be engaged in the engagement slot, so that the cap will be rotatably put on the head, and that the head cannot be rotated. An example of such means is disclosed in Japanese Patent Unexamined Publication No. 50-35540.
In addition, as simple preventing means, seal paint is applied to the outer surface of a head of an adjustment screw in order to check whether or not the adjustment screw has been readjusted.